


   pi = 3.1415926 
   xr = 0.1e-6*100.  ;; m -> cm ;; 200nm  
   Dg = 0.2          ;; cm2 s-1 ;; gas phase diffusion coeff  
   mu = 3.e4         ;; cm s-1 
   gm = 1.e-3        ;; unitless  
   Nr = 2.e5*1.e-6   ;; #/cm3 

   ;; [cm^2/cm^3] * [cm/s] = [1/s] 

   rate = 4. * pi * xr^2 * Nr / ( xr/Dg + 4./(mu*gm) ) 

   ;; hno3 conc (ppm) 

   hno3 = 4.e-4 

   hno3 = hno3 * 1.e6 ;; ppt 

   hno3 = hno3 / (1e12 * 29. / 63.0128) ;; kg(hno3)/kg 

   print("uptake rate : "+rate) 
   print("hno3        : "+hno3) 
   print("hno3 sink   : "+hno3*rate*1800.) 

   ;; monolayer thickness (m) 

   dmono = 4.7742e-10

   ;; hno3 mass per particle 

   area = 4. * 3.1415926 * 0.1e-6^2
   volume = area * dmono 
   mass = volume * 2504.  ;; * kg/m3 

   print("area     : "+area) 
   print("volume   : "+volume) 
   print("mass     : "+mass)

   ;; model time step 

   dtime = 3. * 3600. ;; 1800. 

   ;; coated dust number (#/L) 

   ncoat = hno3 * rate * dtime / mass * 1.e-3 
   print("ncoat (#/L) : "+ncoat) 


